U.S. patent application number 15/409549 was filed with the patent office on 2017-05-11 for magnetic device and method of manufacturing the same.
The applicant listed for this patent is CYNTEC CO., LTD.. Invention is credited to Chih-Siang Chuang, Roger Hsieh, Yi-Min Huang, Cheng-Chang Lee, Chun-Tiao Liu.
Application Number | 20170133149 15/409549 |
Document ID | / |
Family ID | 51551988 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170133149 |
Kind Code |
A1 |
Hsieh; Roger ; et
al. |
May 11, 2017 |
MAGNETIC DEVICE AND METHOD OF MANUFACTURING THE SAME
Abstract
A magnetic device comprises a lead frame, a first core body and
a coil. The lead frame has a first portion and a second portion
spaced apart from the first portion. A first core body is disposed
on the lead frame, wherein the first core body comprises a first
through opening and a second through opening. A coil is disposed on
the first core body, wherein the coil has a first terminal and a
second terminal, wherein the first portion is electrically
connected with the first terminal via the first through opening,
and the second portion is electrically connected with the second
terminal via the second through opening, respectively.
Inventors: |
Hsieh; Roger; (Hsinchu,
TW) ; Lee; Cheng-Chang; (Yunlin County, TW) ;
Liu; Chun-Tiao; (Hsinchu, TW) ; Huang; Yi-Min;
(Hsinchu, TW) ; Chuang; Chih-Siang; (Hsinchu,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CYNTEC CO., LTD. |
HSINCHU |
|
TW |
|
|
Family ID: |
51551988 |
Appl. No.: |
15/409549 |
Filed: |
January 19, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14820558 |
Aug 7, 2015 |
9576710 |
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15409549 |
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13902997 |
May 28, 2013 |
9136050 |
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14820558 |
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61803798 |
Mar 21, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 27/2828 20130101;
H01F 7/06 20130101; H01F 5/003 20130101; Y10T 29/302 20150115; H01F
27/292 20130101; H01F 27/255 20130101; H01F 27/022 20130101; H01F
41/0206 20130101; H01F 41/10 20130101; H01F 27/00 20130101; Y10T
29/49073 20150115; H01F 5/00 20130101; H01F 17/04 20130101; Y10T
29/49075 20150115; H05K 3/301 20130101; H01F 27/29 20130101 |
International
Class: |
H01F 27/29 20060101
H01F027/29; H01F 27/28 20060101 H01F027/28; H01F 27/255 20060101
H01F027/255 |
Claims
1. An inductor, comprising: a magnetic body, wherein a first
through opening is formed on a periphery of the magnetic body; and
a first lead comprising a first conductive part and a second
conductive part electrically connected to the first conductive
part, wherein the first conductive part is disposed on the bottom
surface of the magnetic body and a bottom surface of the first
conductive part is located under said first through opening, and at
least a portion of the second conductive part is disposed in the
first through opening, wherein a conductive path is formed from a
first terminal of a coil of the inductor to the first conductive
part via the second conductive part.
2. The inductor according to claim 1, wherein there is no other
conductive part that is located outside of any outer side surface
of the magnetic body adjacent to the first through opening and used
for soldering with the first terminal of the coil
3. The inductor according to claim 1, wherein the first conductive
part and the second conductive part of the first lead are
integrally formed by metallic material, wherein the bottom surface
of the first conductive part is substantially flat.
4. The inductor according to claim 1, wherein the first through
opening is formed by at least two outer side surfaces of the
periphery of the magnetic body, wherein said two outer side
surfaces are substantially perpendicular to each other.
5. The inductor according to claim 1, wherein a second through
opening is formed on a periphery of the magnetic body, further
comprising a second lead comprising a third conductive part and a
fourth conductive part connected to the third conductive part,
wherein the third conductive part is disposed on the bottom surface
of the magnetic body a bottom surface of the second conductive part
is located under said second through opening, and at least a
portion of the fourth conductive part is disposed in the second
through opening and electrically connected to a second terminal of
the coil.
6. The inductor according to claim 5, wherein the second through
opening is formed by at least two outer side surfaces of the
magnetic body, wherein said two outer surfaces are substantially
perpendicular to each other.
7. The inductor according to claim 1, wherein the top end of the
second conductive part is disposed in the first through
opening.
8. An inductor, comprising: a magnetic core, comprising a first
through opening; a coil disposed on the magnetic body; a first lead
comprising a first conductive part and a second conductive part
electrically connected to the first conductive part, wherein the
first conductive part is disposed on the bottom surface of the
magnetic body and a bottom surface of the first conductive part is
located under said first through opening, and at least a portion of
the second conductive part is disposed in the first through
opening, wherein a conductive path is formed from a first terminal
of a coil to the first conductive part via the second conductive
part; and a molding body, wherein the coil and the second
conductive part are encapsulated by the molding body.
9. The inductor according to claim 8, wherein the first conductive
part and the second conductive part are integrally formed by
metallic material, wherein the bottom surface of the first
conductive part is substantially flat.
10. The inductor according to claim 8, wherein the molding body
encapsulates the magnetic core, the coil and the second conductive
part.
11. The inductor according to claim 8, wherein the magnetic core
further comprises a second through opening, further comprising a
second lead comprising a third conductive part and a fourth
conductive part connected to the third conductive part, wherein the
third conductive part is disposed on the bottom surface of the
magnetic body and a bottom surface of the third conductive part is
located under said second through hole, and at least a portion of
the fourth conductive part is disposed in the second through
opening and electrically connected to a second terminal of the
coil.
12. The inductor according to claim 8, wherein the first through
opening is formed on a first corner of the periphery of the
magnetic body.
13. The inductor according to claim 11, wherein the second through
opening is formed on a second corner of the periphery of the
magnetic body.
14. The inductor according to claim 8, wherein the top end of the
second conductive part is disposed in the first through
opening.
15. The inductor device according to claim 11, wherein the top end
of the fourth conductive part is disposed in the first through
opening.
16. An inductor, comprising: a magnetic body, wherein a first
through opening is formed on a periphery of the magnetic body; and
a first lead comprising a first conductive part and a second
conductive part connected to the first conductive part, wherein the
first conductive part is disposed on the bottom surface of the
magnetic body and a bottom surface of the first conductive part is
located under said first through opening, and at least a portion of
the second conductive part is disposed in the first through
opening, wherein a conductive path is formed from a first terminal
of a coil of the inductor to the first conductive part via the
second conductive part, wherein the first through opening is formed
by at least two outer side surfaces of the periphery of the
magnetic body, wherein said two outer side surfaces are
substantially perpendicular to each other.
17. The inductor according to claim 16, wherein the first
conductive part and the second conductive part are integrally
formed by metallic material, wherein the bottom surface of the
first conductive part is substantially flat.
18. The inductor according to claim 16, wherein a second through
opening is formed on the periphery of the magnetic body, further
comprising a second lead comprising a third conductive part and a
fourth conductive part connected to the third conductive part,
wherein the third conductive part is disposed on the bottom surface
of the magnetic body and a bottom surface of the third conductive
part is located under said second through opening, and at least a
portion of the fourth conductive part is disposed in the second
through hole and electrically connected to a second terminal of the
coil.
19. The inductor according to claim 16, wherein the first through
opening is formed on a first corner of the periphery of the
magnetic body.
20. The inductor according to claim 18, wherein the second through
opening is formed on a second corner of the periphery of the
magnetic body.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/820,558, filed Aug. 7, 2015, which is a
continuation of U.S. patent application Ser. No. 13/902,997, filed
May 28, 2013, which claims the benefit of priority of U.S.
Provisional Application No. 61/803,798, filed Mar. 21, 2013. All of
these applications are incorporated by referenced herein in their
entirety.
BACKGROUND OF THE INVENTION
[0002] I. Field of the Invention
[0003] The present invention relates to a magnetic device and, in
particular, to a magnetic device with electrodes made of a lead
frame.
[0004] II. Description of the Prior Art
[0005] As an inductor has gradually become smaller and thinner, it
is not easy to position the coil accurately which will affect
product yield. The electrodes of the inductor are exposed to the
lateral surface of the inductor so that a fixed space must be kept
in the circuit board to prevent short circuit. Moreover, with the
shrinkage of product size, a bad C-face crack will result from a
bent stress when the electrodes of the inductor are bent during the
molding process.
[0006] So far there are some drawbacks in the various types of
inductors disclosed in the prior arts. In JP4795489B1, the design
of the inductor which needs many electroplating steps induces a lot
of process steps; the material capable of be electroplated is
limited; and the electrodes of the inductor are exposed to the
lateral surface of the inductor. In CN201207320Y, the conductive
wires bent to the bottom of the iron core induce that the iron core
doesn't have a smooth surface. If pressure is still applied in
package process, the iron core easily has a crack.
[0007] Accordingly, the present invention proposes a magnetic
device and a manufacturing method thereof to overcome the
above-mentioned disadvantages.
SUMMARY OF THE INVENTION
[0008] One objective of the present invention is to provide a
magnetic device with bottom electrodes made of a lead frame. The
magnetic device comprises: a lead frame having a first portion and
a second portion spaced apart from the first portion; a first core
body disposed on the lead frame, wherein the first core body
comprises a first through opening and a second through opening; and
a coil disposed on the first core body, wherein the coil has a
first terminal and a second terminal, wherein the first portion is
electrically connected with the first terminal via the first
through opening, and the second portion is electrically connected
with the second terminal via the second through opening,
respectively.
[0009] Preferably, the first portion comprises a first protrusion
and the second portion comprises a second protrusion, wherein the
first protrusion is connected with the first terminal through the
first through opening, and the second protrusion is connected with
the second terminal through the second through opening,
respectively. A first conductive pillar can be disposed in the
first through opening to connect the first portion with the first
terminal, and a second conductive pillar can be disposed in the
second through opening to connect the second portion with the
second terminal, respectively.
[0010] A molding body encapsulates the coil. A first electrode is
disposed on the bottom surface of the first portion and a second
electrode is disposed on the bottom surface of the second portion.
That is, the bottom of each of the first portion and the second
portion of the lead frame is exposed to the bottom of the molding
body such that the first portion and the second portion
respectively serve as a first electrode and a second electrode of
the magnetic device. The main advantages of the magnetic device in
the present invention are described as follows: 1. Adhesion area
between the bottom electrodes of the magnetic device and the
circuit board is maximized to enhance the adhesion strength. 2.
Because of no lateral electrode, product size can be shrunk and
surface utility rate of the circuit board can be raised. 3. The
height and the shape of the protrusions of the lead frame can be
adjusted to be adapted for various types of coils so that it is
easier to weld and position the core body. 4. The lead frame can be
formed by various methods, such as folding, bending, electroplating
or etching.
[0011] Another objective of the present invention is to provide a
method for forming a magnetic device. The method comprises the
steps of: forming a lead frame having a first portion and a second
portion spaced apart from the first portion; disposing a first core
body on the lead frame, wherein the first core body comprises a
first through opening and a second through opening; and disposing a
coil on the first core body, wherein the coil has a first terminal
and a second terminal, wherein the first portion is electrically
connected with the first terminal via the first through opening,
and the second portion is electrically connected with the second
terminal via the second through opening, respectively. In one
embodiment of the magnetic device adapted for SMD technology, the
lead frame can be formed by electroplating or etching.
[0012] Another objective of the present invention is to provide a
method for forming a magnetic device, the method comprising the
steps of: forming a lead frame comprising a first bottom part and a
first protrusion connected to the first bottom part; forming a
first core body, wherein the first core body comprises a first
through opening; placing the first core body on the first bottom
part of the lead frame, with at least a part of the first
protrusion of the lead frame disposed in the first through opening
for electrically connecting with a first terminal of a coil on the
first core body; and encapsulating the first protrusion of the lead
frame and the coil by using a molding material.
[0013] In one embodiment, the first bottom part and the first
protrusion are integrally formed.
[0014] In one embodiment, the lead frame further comprises a second
bottom part and a second protrusion connected to the second bottom
part, and wherein the first core body further comprises a second
through opening, wherein the first core body is placed on the first
bottom part of the lead frame and at least a part of the second
protrusion of the lead frame is disposed in the second through
opening for electrically connecting with a second terminal of the
coil on the first core body. In one embodiment, the first bottom
part and the first protrusion are integrally formed, and the second
bottom part and the second protrusion are integrally formed.
[0015] In one embodiment, the lead frame is formed by
electroplating a conductive pillar on a conductive material.
[0016] In one embodiment, the lead frame is formed by
electroplating a conductive pillar on a copper foil.
[0017] In one embodiment, the lead frame is formed by etching a
metallic substrate.
[0018] In one embodiment, the first protrusion comprises a first
foldable soldering pad.
[0019] In one embodiment, the first protrusion comprises a first
bent portion for connecting with the first terminal.
[0020] In one embodiment, the first through opening is formed with
a first outer side surface of the first core body.
[0021] In one embodiment, the first through opening is formed with
two outer side surfaces of the first core body.
[0022] In one embodiment, the first through opening is formed with
a first outer side surface of the first core body; and the second
through opening is formed with a second outer side surface of the
first core body.
[0023] In one embodiment, the first through opening and the second
through opening are respectively formed with two outer side
surfaces of the first core body.
[0024] In one embodiment, the first through opening and the second
through opening are respectively formed on a periphery of the first
core body, wherein the first protrusion is not extended outside of
any outer side surface of the first core body adjacent to the first
through opening, and the second protrusion is not extended outside
of any outer side surface of the first core body adjacent to the
second through opening.
[0025] The detailed technology and above preferred embodiments
implemented for the present invention are described in the
following paragraphs accompanying the appended drawings for people
skilled in this field to well appreciate the features of the
claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The foregoing aspects and many of the accompanying
advantages of this invention will become more readily appreciated
as the same becomes better understood by reference to the following
detailed description when taken in conjunction with the
accompanying drawings, wherein:
[0027] FIG. 1A is a schematic view of a magnetic device in the
present invention;
[0028] FIG. 1B is an exploded schematic view of the magnetic device
shown in FIG. 1A;
[0029] FIG. 1C is a bottom schematic view of the magnetic device
shown in FIG. 1A;
[0030] FIG. 1D is an exploded schematic view of the magnetic
device, wherein the first core body is a T-core body;
[0031] FIG. 1E is a schematic view of the magnetic device in the
present invention, wherein the first core body is a T-core
body;
[0032] FIG. 2A is a schematic view of a foldable lead frame,
wherein the foldable lead frame is unfolded;
[0033] FIG. 2B is a schematic view of a foldable lead frame;
[0034] FIG. 2C is a schematic view of a magnetic device in the
present invention, wherein the lead frame is foldable;
[0035] FIG. 2D is a schematic view of a bent lead frame;
[0036] FIG. 3 is the process flow of manufacturing a magnetic
device in FIG. 1A, FIG. 1E, FIG. 2C and FIG. 4A;
[0037] FIG. 4A is a schematic view of a magnetic device in the
present invention, wherein the lead frame is formed by
electroplating or etching;
[0038] FIG. 4B is an exploded schematic view of the magnetic device
shown in FIG. 4A.
DETAILED DESCRIPTION OF THE INVENTION
[0039] The detailed explanation of the present invention is
described as following. The described preferred embodiments are
presented for purposes of illustrations and description and they
are not intended to limit the scope of the present invention.
[0040] The present invention discloses a magnetic device in which a
first portion and a second portion of a lead frame respectively are
electrically connected with a first terminal and a second terminal
of a coil through a first through opening and a second through
opening of a core body to serve as a first electrode and a second
electrode on the bottom of the magnetic device.
[0041] FIG. 1A is a schematic view of a magnetic device 10 in the
present invention. FIG. 1B is an exploded schematic view of the
magnetic device 10 shown in FIG. 1A. FIG. 1C is a bottom schematic
view of the magnetic device 10 shown in FIG. 1A. FIG 1D is an
exploded schematic view of the magnetic device 10, wherein the
first core body is a T-core body. FIG. 1E is a schematic view of
the magnetic device 10 in the present invention, wherein the first
core body is a T-core body. The magnetic device 10 includes a lead
frame 11, a first core body 12, a coil 13 and a molding body
14.
[0042] The lead frame 11 has a first portion 11a and a second
portion 11b spaced apart from the first portion 11a. Optionally,
the first portion 11a can comprise a first protrusion 15a, and the
second portion 11b can comprise a second protrusion 15b. For a
better electrical connection between the lead frame 11 and the coil
13, the top of the first protrusion 15a is higher than that of the
first through opening 12a, and the top of the second protrusion 15b
is higher than that of the second through opening 12b. Preferably,
the first portion 11a further comprises a third protrusion 15c, and
the second portion 11b further comprises a fourth protrusion 15d,
wherein the first protrusion 15a, the second protrusion 15b, the
third protrusion 15c and the fourth protrusion 15d surround the
first core body 12. In one embodiment (see FIG. 2A, FIG. 2B and
FIG. 2C), the first protrusion 15a comprises a first foldable
soldering pad 17a, and the second protrusion 15b comprises a second
foldable soldering pad 17b. Specifically speaking, the first
portion 11a of the lead frame 11 has a first foldable soldering pad
17a folded to serve as the first protrusion 15a, and the second
portion 11b of the lead frame 11 has a second foldable soldering
pad 17b folded to serve as the second protrusion 15b. In another
embodiment (see FIG. 2D), the first protrusion 15a comprises a
first bent portion for connecting with a first terminal of a coil,
and the second protrusion 15b comprises a second bent portion for
connecting with the second terminal of a coil. For example, the
first protrusion 15a, the second protrusion 15b, the third
protrusion 15c, the fourth protrusion 15d can be formed by bending
four segments of a flat lead frame 11. Moreover, the lead frame 11
can be also formed by electroplating or etching (described
hereafter).
[0043] A first core body 12 is disposed on the lead frame 11. The
first core body 12 is a magnetic core body. The first core body 12
can be made of any suitable magnetic powder, such as Fe alloy
powder (Fe--Cr--Si, Fe--Al--Cr or Fe--Si--Al), ferrite powder
(Ni--Zn ferrite or Mn--Zn ferrite), amorphous alloy powder or Fe
powder. By pressing-molding process (e.g., heating or sintering),
the magnetic powder and adhesive are mixed to form the first core
body 12. The first core body 12 can have any suitable shape
according design or practical application.
[0044] The first core body 12 comprises a first through opening 12a
and a second through opening 12b. There are many different ways to
locate the first through opening 12a and the second through opening
12b: in one embodiment, each of the first through opening 12a and
the second through opening 12b is formed inside the first core body
12; in another embodiment, each of the first through opening 12a
and the second through opening 12b is formed with one side of the
opening aligned with one edge of the first core body 12; and in yet
another embodiment, each of the first through opening 12a and the
second through opening 12b is formed with two sides of the opening
aligned with two edges of the first core body 12 respectively.
[0045] A coil 13 is disposed on the first core body 12. The coil 13
can be formed by wrapping round-wire, flat-wire or enameled-wire
made of Cu or Ag. The coil 13 can be made of a conductive wire or a
conductive pattern formed by any known technology, such as
electroplating, etching, printing process or film process. The coil
13 has a first terminal 13a and a second terminal 13b. The first
portion 11a is electrically connected with the first terminal 13a
via the first through opening 12a, and the second portion 15b is
electrically connected with the second terminal 13b via the second
through opening 12b, respectively. Preferably, the first portion
llacomprises a first protrusion 15a and the second portion 11b
comprises a second protrusion 15b, wherein the first protrusion 15a
is connected with the first terminal 13a through the first through
opening 12a, and the second protrusion 15b is connected with the
second terminal 13b through the second through opening 12b,
respectively. In one embodiment, the top end of the first
protrusion 15a can be disposed in the first through opening 12a,
and the top end of the second protrusion 15b can be disposed in the
second through opening 12b. In other words, refer to FIG. 1E and
FIG. 4A, the first joined point 16a of the first terminal 13a and
the first protrusion 15a can be inside the first through opening
12a, and the second joined point 16b of the second terminal 13b and
the second protrusion 15b can be inside the second through opening
12b. In another embodiment, at least one portion of the first
protrusion 15a is disposed outside the first through opening 12a,
and at least one portion of the second protrusion 15b is disposed
outside the second through opening 12b. In other words, refer to
FIG. 1A, the first joined point 16a of the first terminal 13a and
the first protrusion 15a is substantially higher than the top of
the first through opening 12a, and the second joined point 16b of
the second terminal 13b and the second protrusion 15b is
substantially higher than the top of the second through opening
12b.
[0046] A first conductive pillar (not shown) can be disposed in the
first through opening 12a to connect the first portion 11a with the
first terminal 13a , and a second conductive pillar (not shown) can
be disposed in the second through opening 12b to connect the second
portion 11b with the second terminal 13b, respectively. It has been
disclosed in U.S. patent application Ser. No. 13/179,884, filed
Jul. 11, 2011.
[0047] There are many different ways to dispose the coil 13 on the
first core body 12. In one embodiment (see FIG. 1A and FIG. 1B),
the first core boy 12 has a first surface 12c which is
substantially flat, wherein the coil 13 is disposed on the first
surface 12c of the first core body 12. In another embodiment (see
FIG. 1E, FIG. 2C and FIG. 4A), the first core boy 12 (e.g., T-core)
comprises a plate 12e and a pillar 12f having a top end and a
bottom end, wherein the bottom end of the pillar 12f is connected
to the plate 12e, wherein the coil 13 is disposed on the plate 12e
and winded around the pillar 12f. In one embodiment, the magnetic
device 10 further comprises a second core body (not shown), wherein
the coil 13 is disposed between the first core body 12 and the
second core body. The material of the first core body 12 can be the
same as that of the second core body or different from that of the
second core body.
[0048] The second core body is a magnetic core body. The second
core body can be made of any suitable magnetic powder, such as Fe
alloy powder (Fe--Cr--Si, Fe--Al--Cr or Fe--Si--Al), ferrite powder
(Ni--Zn ferrite or Mn--Zn ferrite), amorphous alloy powder or Fe
powder. By pressing-molding process (e.g., heating or sintering),
the magnetic powder and adhesive are mixed to form the second core
body. The second core body can have any suitable shape according
design or practical application.
[0049] A molding body 14 encapsulates the coil 13. A first
electrode is disposed on the bottom surface of the first portion
11a and a second electrode is disposed on the bottom surface of the
second portion 11b. That is, the bottom of each of the first
portion 11a and the second portion 11b of the lead frame 11 is
exposed to the bottom of the molding body 14 such that the first
portion 11a and the second portion respectively 11b serve as a
first electrode and a second electrode of the magnetic device 10.
The first electrode and the second electrode of the magnetic device
10 can be formed by printing or electroplating.
[0050] FIG. 3 is the process flow of manufacturing a magnetic
device 10, 20, 30 in FIG. 1A, FIG. 1E, FIG. 2C and FIG. 4A.
[0051] In step 31, form a lead frame 11 having a first portion 11a
and a second portion 11b spaced apart from the first portion 11a.
Optionally, the first portion 11a can comprise a first protrusion
15a and the second portion 11b can comprise a second protrusion
15b.
[0052] In one embodiment of the magnetic device adapted for SMD
technology, the lead frame can be formed by electroplating or
etching. FIG. 4A is a schematic view of a magnetic device 30 in the
present invention, wherein the lead frame 11 is formed by
electroplating or etching. FIG. 4B is an exploded schematic view of
the magnetic device 30 shown in FIG. 4A. To form the lead frame 11,
for example, Sn or Ni/Sn can be electroplated on a conductive
material (e.g., copper foil) which can be made of Cu, or a
conductive material (e.g., a metallic substrate) can be etched. In
this case, each of the first protrusion 15a and the second
protrusion 15b is a conductive pillar. The advantages are listed as
below: 1. The magnetic device has a complete electrode plane, and
the plane shape can be adjusted according to design demand.
Compared to the lead frame formed by bending, the bottom electrodes
of the magnetic device are complete, and adhesion area between the
bottom electrodes of the magnetic device and the circuit board is
maximized (utility rate of electrode area is larger than 90%) to
enhance the adhesion strength. 2. The height and the shape of the
protrusive conductive pillars can be adjusted to be adapted for
various types of coils so that it is easier to weld and position
the core body. 3. The design of the bottom electrodes of the
magnetic device can reduce the distance between devices on the
circuit board. 4. The lead frame can be directly adapted for SMD
technology, so the electroplating steps in the process of the
magnetic device can be saved and the material capable of be
electroplated is not limited.
[0053] In step 32, dispose a first core body 12 on the lead frame
11, wherein the first core body 12 comprises a first through
opening 12a and a second through opening 12b. In one embodiment,
the magnetic device further comprises a second core body (not
shown), wherein the coil is disposed between the first core body 12
and the second core body. The first core body 12 (or the second
core body) is a magnetic core body. The material of the first core
body 12 can be the same as that of the second core body or
different from that of the second core body. The first core body 12
(or the second core body) can be formed by hot-pressing molding or
cold-pressing molding, preferably, cold-pressing molding.
[0054] In step 33, dispose a coil 13 on the first core body 12,
wherein the coil 13 has a first terminal 13a and a second terminal
13b, wherein the first portion 11a is electrically connected with
the first terminal 13a via the first through opening 12a, and the
second portion 11b is electrically connected with the second
terminal 13b via the second through opening 12b, respectively.
Preferably, the first portion 11a comprises a first protrusion 15a
and the second portion 11b comprises a second protrusion 15b ,
wherein the first protrusion 15a is connected with the first
terminal 13a through the first through opening 12a, and the second
protrusion 15b is connected with the second terminal 13b through
the second through opening 12b, respectively. A first conductive
pillar (not shown) can be disposed in the first through opening 12a
to connect the first portion 11a with the first terminal 13a , and
a second conductive pillar (not shown) can be disposed in the
second through opening 12b to connect the second portion 11b with
the second terminal 13b, respectively. The coil 13 can be formed by
wrapping round-wire, flat-wire or enameled-wire made of Cu or Ag.
The coil 13 can be made of a conductive wire or a conductive
pattern formed by any known technology, such as electroplating,
etching, printing process or film process.
[0055] In step 34, form a molding body 14 to encapsulate the coil
13. The molding body 14 can be formed by hot-pressing molding or
cold-pressing molding, preferably, hot-pressing molding. A first
electrode is disposed on the bottom surface of the first portion
11a and a second electrode is disposed on the bottom surface of the
second portion 11b. That is, the bottom of each of the first
portion lla and the second portion 11b of the lead frame 11 is
exposed to the bottom of the molding body 14 such that the first
portion 11a and the second portion 11b respectively serve as a
first electrode and a second electrode of the magnetic device. The
first electrode and the second electrode of the magnetic device can
be formed by printing or electroplating.
[0056] Detailed process is listed as below. A lead frame is formed
by punching, electroplating or etching, and then the lead frame is
dispensed. A core body is formed by cold-pressing molding and
connected to the lead frame. The coil is disposed on the core body,
and the terminals of the coil are electrically connected to the
protrusions of the lead frame by spot welding or laser welding plus
wire-head trimming. A molding body is formed to encapsulate the
coil by hot-pressing molding and curing. The electrodes of the
magnetic device are formed by electroplating or printing. Finally,
the final product is done by trimming and passing electrical
testing.
[0057] The above disclosure is related to the detailed technical
contents and inventive features thereof. People skilled in this
field may proceed with a variety of modifications and replacements
based on the disclosures and suggestions of the invention as
described without departing from the characteristics thereof.
Nevertheless, although such modifications and replacements are not
fully disclosed in the above descriptions, they have substantially
been covered in the following claims as appended.
* * * * *